The use of disposable elastomeric ambulatory infusion devices have gain wide acceptance due to its ease of use, safe and effective means of drug delivery in non hospital based settings. There are however limitations in situations where infusions are not required immediately after filling e.g. a patient needing multiple doses over a long duration. The filled devices that are used later may not have the intended flow rates as the pressure generated by the elastomer would typically change with time. Another drawback of known devices is the variation in pump pressure makes simultaneously multiple filling impractical, weaker pumps would fill up easily and end up with larger volume of medication than stronger pumps.